David Malet Armstrong (8 July 1926?13 May 2014) has been one of the most influential contemporary metaphysicians working in the analytic tradition and surely the greatest 20th century Australian philosopher. His main merit is to have reestablished metaphysics as a respectable branch of philosophy placing it at the centre of the philosophical debate, and giving it the status of an authoritative and competent interlocutor of both rational and empirical sciences. By means of a rigorously argumentative approach and a sharp prose, Armstrong has built a whole metaphysical system, that is, a comprehensive and unified picture of the fundamental structure of the world. The various chapters of